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72 lines
1.9 KiB
72 lines
1.9 KiB
/* 16-bit signed integer dot product |
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* SSE2 version |
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* Copyright 2004 Phil Karn |
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* May be used under the terms of the GNU Lesser General Public License (LGPL) |
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*/ |
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#define _XOPEN_SOURCE 600 |
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#include <stdlib.h> |
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#include <memory.h> |
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#include "fec.h" |
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struct dotprod { |
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int len; /* Number of coefficients */ |
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/* On a SSE2 machine, these hold 8 copies of the coefficients, |
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* preshifted by 0,1,..7 words to meet all possible input data |
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* alignments (see Intel ap559 on MMX dot products). |
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*/ |
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signed short *coeffs[8]; |
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}; |
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long dotprod_sse2_assist(signed short *a,signed short *b,int cnt); |
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/* Create and return a descriptor for use with the dot product function */ |
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void *initdp_sse2(signed short coeffs[],int len){ |
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struct dotprod *dp; |
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int i,j,blksize; |
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if(len == 0) |
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return NULL; |
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dp = (struct dotprod *)calloc(1,sizeof(struct dotprod)); |
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dp->len = len; |
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/* Make 8 copies of coefficients, one for each data alignment, |
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* each aligned to 16-byte boundary |
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*/ |
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for(i=0;i<8;i++){ |
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blksize = (1+(len+i-1)/8) * 8*sizeof(signed short); |
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posix_memalign((void **)&dp->coeffs[i],16,blksize); |
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memset(dp->coeffs[i],0,blksize); |
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for(j=0;j<len;j++) |
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dp->coeffs[i][j+i] = coeffs[j]; |
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} |
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return (void *)dp; |
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} |
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/* Free a dot product descriptor created earlier */ |
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void freedp_sse2(void *p){ |
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struct dotprod *dp = (struct dotprod *)p; |
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int i; |
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for(i=0;i<8;i++) |
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if(dp->coeffs[i] != NULL) |
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free(dp->coeffs[i]); |
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free(dp); |
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} |
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/* Compute a dot product given a descriptor and an input array |
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* The length is taken from the descriptor |
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*/ |
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long dotprod_sse2(void *p,signed short a[]){ |
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struct dotprod *dp = (struct dotprod *)p; |
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int al; |
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signed short *ar; |
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ar = (signed short *)((int)a & ~15); |
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al = a - ar; |
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/* Call assembler routine to do the work, passing number of 8-word blocks */ |
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return dotprod_sse2_assist(ar,dp->coeffs[al],(dp->len+al-1)/8+1); |
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}
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